package com.itheima.domain;

/**
 *
 * @Title :
 * @Description : 观察者接口

 * @param null
 * @return
 *
 * @user : Yrd
 * @date : 2021-11-02 14:40
 */
public interface Observer {

    //method to update the observer, used by subject
    public void update();

    //attach with subject to observe
    public void setSubject(Subject subject);
}
